The initial drilling survey revealed that there are many caves along with Binjiang Road Station—Wutang Village Station at proposed Nanjing Metro Line 3. Through the analysis of geological background,and combined with geophysical exploration, borehole data, found that the karst was controlled by faults significantly, the size of cave is small, but is quantity. The distribution of cave is selective, multi layer and other features.Analysis the influence of cave to the stability of surrounding rock in different situations by numerical.The results show that, the plastic zone of surrounding rock change with the size and location of cave. The plastic zone increase with cave size. The plastic zone's area is largest when the cave in the spandrel, and is smallest when cave in the hance. After the tunnel excavation, the vault and dome are the most easily damaged place. It has the greatest impact on the stability of surrounding rock when the cave in the spandrel. beaded cave is more harmful than a single cave in similar conditions.